Agenesis of the corpus callosum: limits of functional compensation

Two patients with radiologically confirmed total agenesis of the corpus callosum, and free of gross focal hemispheric pathology, received a battery of lateralized and free-field language and perceptual-motor tests. These tasks allowed a comparison of (1) agenic findings with previous results from surgical commissurotomy patients, and (2) the inter- and intrahemispheric performance for each agenic subject. In general, the results indicate that the two agenic patients do not demonstrate the marked deficits of cross-integration reported after commissurotomy. However, there was an upper limit to their integrative capacity for visual, and to an even greater extent, for fine motor and kinesthetically mediated performance. The tasks that proved particularly difficult appeared to have common factors which may be related to functional capabilities of the ipsilateral motor pathways and anterior commissure.